ﺑﺮرﺳﻲ اﺛﺮ ﭘﺮاﻳﻤﻴﻨﮓ ﺗﻮأم ﺑﺬرﻫﺎي ﮔﻨﺪم ﺑﺎ اﺳﻴﺪ ﺳﺎﻟﻴﺴﻴﻠﻴﻚ و ﭘﺮاﻛﺴﻴﺪ ﻫﻴﺪروژن ﺑﺮاي اﻟﻘﺎء ﺗﺤﻤﻞ ﺑﻪ ﺷﻮري

Salicylic acid and hydrogen peroxide priming as a means to induce salt stress tolerance of wheat

دراﻳﻦ ﭘﮋوﻫﺶ، اﺛﺮ ﭘﺮاﻳﻤﻴﻨﮓ اﺳﻴﺪ ﺳﺎﻟﻴﺴﻴﻠﻴﻚ، ﭘﺮاﻛﺴﻴﺪ ﻫﻴﺪروژن و ﭘﺮاﻳﻤﻴﻨﮓ ﺗﻮأم اﺳﻴﺪ ﺳﺎﻟﻴﺴﻴﻠﻴﻚ و ﭘﺮاﻛﺴﻴﺪ ﻫﻴﺪروژن ﺑﺮ ﺑﻬﺒﻮد ﺗﺤﻤﻞ ﺑﻪ ﺷﻮري داﻧﻪرﺳﺖﻫﺎي ﮔﻨﺪم )Triticum aestivum L. cv Mihan( ﺑﺮرﺳﻲ ﺷﺪ. ﺑﺬرﻫﺎ ﺑﻪ ﻣﺪت 24 ﺳﺎﻋﺖ داﺧﻞ آب ﻣﻘﻄﺮ )ﺷﺎﻫﺪ(، ﻏﻠﻈﺖﻫﺎي ﻣﺨﺘﻠﻒ اﺳﻴﺪ ﺳﺎﻟﻴﺴﻴﻠﻴﻚ )0/1، 0/5 و 1 ﻣﻴﻠﻲ ﻣﻮﻻر( و ﭘﺮاﻛﺴﻴﺪﻫﻴﺪروژن )1، 20 و 200 ﻣﻴﻠﻲ ﻣﻮﻻر( ﺧﻴﺴﺎﻧﺪه ﺷﺪﻧﺪ. ﭘﺲ از ﮔﺬﺷﺖ ﻳﻚ ﻫﻔﺘﻪ، داﻧﻪ رﺳﺖ ﻫﺎ ﺑﻪ ﻣﺤﻴﻂ ﻛﺸﺖ ﻫﻴﺪروﭘﻮﻧﻴﻚ ﺣﺎوي ﻣﺤﻠﻮل ﻏﺬاﻳﻲ ﻫﻮﮔﻠﻨﺪ ﻣﻨﺘﻘﻞ ﺷﺪﻧﺪ. آزﻣﺎﻳﺶ در ﻗﺎﻟﺐ ﻃﺮح ﺑﻠﻮكﻫﺎي ﻛﺎﻣﻞ ﺗﺼﺎدﻓﻲ ﺑﺎ ﭼﻬﺎر ﺗﻜﺮار اﺟﺮا ﺷﺪ. ﺷﻮري 200 ﻣﻴﻠﻲﻣﻮﻻر وزن ﺧﺸﻚ اﻧﺪام ﻫﻮاﻳﻲ داﻧﻪ رﺳﺖﻫﺎي ﮔﻨﺪم را 25 درﺻﺪ ﻛﺎﻫﺶ داد. ﭘﺮاﻳﻤﻴﻨﮓ ﺑﺬر و ﺑﺎ ﭘﺮاﻛﺴﻴﺪ ﻫﻴﺪروژن 20 ﻣﻴﻠﻲﻣﻮﻻر ﺑﺎﻋﺚ ﻛﺎﻫﺶ ﺗﻮﻟﻴﺪ ﻣﺎﻟﻮن دي آﻟﺪﺋﻴﺪ در ﺷﺮاﻳﻂ ﺗﻨﺶ ﺷﻮري ﮔﺮدﻳﺪ. ﺑﺎ ﻛﺎﻫﺶ ﻣﺎﻟﻮن دي آﻟﺪﺋﻴﺪ در داﻧﻪرﺳﺖﻫﺎي ﺣﺎﺻﻞ از ﭘﺮاﻳﻤﻴﻨﮓ ﭘﺮاﻛﺴﻴﺪ ﻫﻴﺪروژن، آﺳﻴﺐ ﺷﻮري ﺑﺮ ﻇﺮﻓﻴﺖ ﻓﺘﻮﺳﻨﺘﺰي و وزن ﺧﺸﻚ ﺗﺨﻔﻴﻒ ﻳﺎﻓﺖ. ﺑﺎاﻳﻨﻜﻪ ﺗﻴﻤﺎر ﭘﺮاﻳﻤﻴﻨﮓ اﺳﻴﺪ ﺳﺎﻟﻴﺴﻴﻠﻴﻚ ﻧﺘﻮاﻧﺴﺖ ﺑﺎﻋﺚ ﺗﺨﻔﻴﻒ اﺛﺮات ﺗﻨﺶ ﺷﻮري ﺑﺮ رﺷﺪ و ﻓﺘﻮﺳﻨﺘﺰ ﮔﻨﺪم ﺷﻮد، داﻧﻪرﺳﺖﻫﺎي رﺷﺪ ﻳﺎﻓﺘﻪ از ﭘﺮاﻳﻤﻴﻨﮓ ﺗﻮأم اﺳﻴﺪ ﺳﺎﻟﻴﺴﻴﻠﻴﻚ و ﭘﺮاﻛﺴﻴﺪ ﻫﻴﺪروژن ﻣﻘﺎوﻣﺖ ﺑﻴﺸﺘﺮي ﺑﻪ ﺗﻨﺶ ﺷﻮري ﻧﺸﺎن دادﻧﺪ. اﻳﻦ اﻓﺰاﻳﺶ ﻣﻘﺎوﻣﺖ ﺑﺎ اﻓﺰاﻳﺶ 45 درﺻﺪي )ﻧﺴﺒﺖ ﺑﻪ ﺷﺎﻫﺪ( ﻣﻘﺪار ﻓﻨﻞ ﻛﻞ و ارﺗﻘﺎء 37 درﺻﺪي ﻣﻴﺰان ﻓﻌﺎﻟﻴﺖ آﻧﺰﻳﻢ ﻛﺎﺗﺎﻻز ﻫﻤﺮاه ﺑﻮد. درﻧﺘﻴﺠﻪ ﺷﺎﺧﺺ ﭘﺮاﻛﺴﻴﺪاﺳﻴﻮن ﻟﻴﭙﻴﺪﻫﺎ در ﺗﻴﻤﺎر ﺗﻮأم اﺳﻴﺪ ﺳﺎﻟﻴﺴﻴﻠﻴﻚ و ﭘﺮاﻛﺴﻴﺪ ﻫﻴﺪروژن ﻛﺎﻫﺶ ﻣﻌﻨﻲ دار ﻧﺸﺎن داد. ﻫﻤﭽﻨﻴﻦ ﭘﺮاﻳﻤﻴﻨﮓ ﺗﻮأم اﺳﻴﺪ ﺳﺎﻟﻴﺴﻴﻠﻴﻚ و ﭘﺮاﻛﺴﻴﺪ ﻫﻴﺪروژن ﺑﺎﻋﺚ ﺗﺨﻔﻴﻒ اﺛﺮات ﺗﻨﺶ ﺷﻮري ﺑﺮ ﻇﺮﻓﻴﺖ ﻓﺘﻮﺷﻴﻤﻴﺎﻳﻲ ﻓﺘﻮﺳﻴﺴﺘﻢ II ﮔﺮدﻳﺪ.

In this study, we investigated the role of salicylic acid (SA) and hydrogen peroxide (H2O2) priming in ameliorating salinity stress on wheat (Triticum aestivum L. cv Mihan) grown under hydroponic culture. Seeds of wheat were primed in distilled water (control), as well as different solutions of salicylic acid (0.1, 0.5 and 1 mM) and/or H2O2 (1, 20 and 200 mM) for 24 h at 25°C. Seven-day-old seedlings were transferred to Hoagland nutrient solution. Experiments were undertaken in complete randomized block design using 4 independent replications. Salinity stress drastically affected the plants as indicated by decreased biomass of shoots (about 25%). However, H2O2 priming at 20 mM raised free radical scavenging activities of wheat leaf, as evaluated by decrease in malondialdehyde (MDA) levels. These results indicated that H2O2 priming could prevent negative effects of salinity stress on the biomass and photosystem performance. While SA priming could not ameliorate the negative effect of salt on wheat seedlings, the use of both SA and H2O2 as priming agents had the most significant alleviating effect against NaCl stress. This ameliorative effect was achieved through stimulation of catalase activity (about 37%) and non-enzymatic (phenols) antioxidants (about 45%) and lowering tissue MDA contents. These results further confirm that the use of both SA and H2O2 as priming agents participated in the protection of membranes against the destabilizing effect of salt stress. Additionally, the use of both SA and H2O2 as priming agents mitigated the negative effects of salinity on the photochemical efficiency of PSII.